Coordination chemistry of phosphine-derived heteropolydentate ligands

In this research project a variety of heteropolydentate phosphine ligands have been synthesized and characterized, and their coordination chemistry has been studied with a number of metal ions.; In Section I, the synthesis, spectroscopic characterization, and reactions of the complexes of the type HRh{dollar}{lcub}{dollar}(P(OMe){dollar}sb2{dollar}O) {dollar}sb2{dollar}X{dollar}{rcub}sb2{dollar}L (X = H, BF{dollar}sb2{dollar}; L = CO, phosphine) are discussed. The complexes with L = CO complexes are found to be reactive towards phenyl isocyanate but not towards CO{dollar}sb2{dollar} or CS{dollar}sb2{dollar}. The crystal structure of (PPh{dollar}sb2{dollar}Me) HRh-{dollar}{lcub}{dollar}(P(OMe){dollar}sb2{dollar}O) {dollar}sb2{dollar}H{dollar}{rcub}sb2{dollar} has been determined, and it has been found that one of the phosphite/phosphito rings is planar and the other significantly non-planar.; In Section II, the syntheses and spectroscopic characterization of a number of bidentate ligands, Ph{dollar}sb2{dollar}PC(O)Me, Ph{dollar}sb2{dollar}P(2-SC{dollar}sb4{dollar}H{dollar}sb3{dollar}), PhP(2-SC{dollar}sb4{dollar}H{dollar}sb3{dollar}){dollar}sb2{dollar}, Ph{dollar}sb2{dollar}PCN, Ph{dollar}sb2{dollar}PCH{dollar}sb2{dollar}NC{dollar}sb5{dollar}H{dollar}sb{lcub}10{rcub}{dollar}, Ph{dollar}sb2{dollar}PCH(Ph)NC{dollar}sb5{dollar}H{dollar}sb{lcub}10{rcub}{dollar} and (Ph{dollar}sb2{dollar}PCH{dollar}sb2{dollar})NPr{dollar}sp{lcub}rm n{rcub}{dollar}, are discussed. Most of these ligands form stable monometallic complexes with Mo and Pt-group metals. Attempts to form dinuclear complexes from these mononuclear complexes lead either to ligand decomposition or to ligand-exchange products. The structure suggested for a previously reported homodinuclear complex, ((CO){dollar}sb4{dollar}Mo(Ph{dollar}sb2{dollar}PCN)) {dollar}sb2{dollar}, containing head to tail bridging Ph{dollar}sb2{dollar}PCN ligand, has been confirmed by multinuclear NMR and IR spectroscopic studies.; In Section III, the preparation and characterization of a series of bis(phosphine)polyether ligands of the type PPh{dollar}sb2{dollar} (CH{dollar}sb2{dollar}CH{dollar}sb2{dollar}O){dollar}sb{lcub}rm n{rcub}{dollar}CH{dollar}sb2{dollar}CH{dollar}sb2{dollar}PPh{dollar}sb2{dollar} (n = 3{dollar}-{dollar}5) are discussed. A number of complexes of Pd(II), Pt(II), Mo(O) and Ru(II) metal ions have been prepared and characterized by {dollar}sp{lcub}13{rcub}{dollar}C and {dollar}sp{lcub}31{rcub}{dollar}P NMR spectroscopy. The Pt(II), Pd(II) and Ru(II) metallacrowns occur as mixtures of several conformers. The various conformers of Pt and Ru metallacrown ethers are separable but those of Pd reequilibrate. These metallacrown ethers solubilize alkali metal salts from non-polar solvents and form 1:1 hard/soft bimetallic complexes. They exhibit size-selectivity for different metal ions. The ether O's can also chelate to metal ions forming stable cationic complexes. The metallacrowns can also coordinate soft metal ions, such as Ru(II) and Hg(II), in the cavity to form either 1:1 or 1:2 stable soft/soft bimetallic complexes. The X-ray crystal structures of two of the complexes have been determined, and these have been used to estimate the cavity size and to determine the conformations of the crowns.